The present invention relates to an improved vacuum sweep apparatus for use in an air-filter system of the type having a plurality of air-filter bags which are cleaned periodically by applying a vacuum to the bags.
One type of air-filter system known in the prior art employs a plurality of upright filter bags mounted on a support plate and communicating at their lower ends with openings in the plate. Unfiltered air introduced into the bags through the plate openings is filtered by its passage through the bags. The bags are cleaned periodically to remove accumulated filtrate by a vacuum sweep device having a rotating vacuum arm and a planar head member rigidly mounted on the arm for movement against the lower side of the plate. As the arm is rotated, apertures in the head member are brought into registry with successive openings in the plate, connecting the vacuum device with the air-filter bags associated with those openings.
During operation of the just-described sweep device, variations in the planarity of the support plate, and variations in the tilt of the rotational axis of the sweep arm cause the head member to move in and out of contact with the lower side of the plate as the vacuum arm rotates. At arm positions where the head member is out of contact with the plate, air passages formed between plate openings and in-register head apertures are substantially unsealed, reducing the vacuum applied to the associated filter bags. Filter bags which are inadequately cleaned for this reason function inefficiently in filtering.
An important object of the present invention is to provide, in a vacuum sweep device used in an air-filter system, a sweep apparatus having an articulated vacuum head which is movable multidirectionally to remain in sealed contact with one side of a bag-support plate in the system as the vacuum device is moved with respect to the plate.
Another object of the invention is to provide, in such apparatus, an apron portion which is adapted to cover a plate opening completely as the vacuum head is moved toward a position communicating that opening with an aperture in the vacuum head.
It is another object of the invention to provide in this apparatus, a plurality of radially spaced apertures which are dimensioned to produce, when in registry with associated radially spaced openings in a bag-support plate, substantially uniform air-flow rates.
Still another object of the present invention is to provide such sweep apparatus which is easily adapted for use in pre-existing air-filter systems.
The sweep apparatus of the present invention is constructed for use in an air-filter system which includes a plate having an array of openings, and a hollow sweep arm mounted on one side of the plate for rotational movement with respect thereto. The apparatus includes a base conduit mounted on the arm, in fluid communication therewith, a head conduit, and a flexible, fluid-tight skirt joining the base and head conduits in sealed fluid communication. The skirt accommodates limited multidirectional movement of the head conduit with respect to the base conduit. The head conduit is biased toward the plate so that as the arm is rotated, an apertured plate-contact member on the head is pressed against the plate to seal the air-flow passages formed by successive registries between openings in the plate and an aperture in the plate-contact member.
In a preferred embodiment of the invention, the plate-contact member includes an apron portion adapted to cover a plate opening completely as the head conduit is moved toward a position communicating that opening with an aperture in the contact member. Also in a preferred embodiment, the plate-contact member includes plural radially spaced apertures adapted for successive registries with associated radially spaced plate openings, where radially adjacent apertures are dimensioned to produce, when in registry with associated plate openings, substantially uniform air-flow rates.
These and other objects and features of the present invention will become more fully apparent when the following detailed description of a preferred embodiment of the invention is read in conjunction with the accompanying drawings, wherein: